A.bac: Protein Synthesis Inhibitors

Question 1

50S Antibacterial agents

Answer 1

50S➡️Macrolides: Erythromycin, Azithromycin, Clarithromycin
Chloramphenicol, Lincosamides, Clinda
30S➡️ AG: Genta, Strepto, Kana
Tetra: T, Doxy, Mino

Question 2

Bacteriostatic antibacterials:

Answer 2

TEST CC: Tetra, Eryth, Sulfa drugs, Trimetho, Clinda, Chloram

Question 3

Macrolides chemical struc. and CI

Answer 3

Large lactones ring of 12 or 14 or 16 atoms are att. to amino sugar (hexose) & neutral sugar by glycosidic link.
CI hepatic failure.

Question 4

These macrolides produce KETAL metabolite resp for GI irritation.
CYP3A4 inhibitors for macrolides

Answer 4

Eryth and Clarith, also potent CYP3A4 inhibitors whereas Azith is weak.

Question 5

Eryth chem. struc, common SE and stability

Answer 5

Lactone ring + desoamine (amino sugar) + cladinose (neutral sugar).
Unstable to acids, bases & high temperature.

Question 6

Azith stability and phkinetics

Answer 6

Stable to acids, bases & high temp, thus less gastric upset.
Long half life, greater and longer tissue penetration and covers H. influenza.

Question 7

Clarith phkinetics

Answer 7

The enhanced lipophilic allows for lower or less frequent doses

Question 8

What drugs potentiate this Digoxin toxicity

Answer 8

Macrolides: Eryth and Clarith, Tetracyclines

*and Macrolides may potentiate Theophylline levels also.

Question 9

With Clinda this is taken with caution and require monitoring in patient receiving what drug tx?

Answer 9

Warfarin— INR

Question 10

drug of choice in traveler diarrhea for person traveling to Thailand.
Prophylaxis?

Answer 10

Azith

Doxy- prophy

Question 11

Erythromycin is effective against?
Erythromycin estolate side effects?
Macrolides storages

Answer 11

gram +ve cocci
SEs reversible cholestatic hepatitis, jaundice, and
fever
Eryth -ref, A and C room temp

Question 12

Tet. t1/2 is shortened by CYP450 induction of what drugs and bev.?

Answer 12

Carbamazepine
Phenytoin
Barbiturates
Chronic alcohol intake

Question 13

Tet can stain teeth and discoloration leading to?

Answer 13

Deformity and growth intake, teeth fluorescence, discoloration and enamel dysplasia

Question 14

Tet chemical instability and structure.

Answer 14

Tetracycline a-stereo orientation of the C4 dimethylamino-moiety is essential for the bioactivity.
Epitetracycline is inactive drug.

Question 15

Tet MOA

Answer 15

Enter cells by passive diffusion or by (in part) active transport. Once inside the cell, tet bind REVERSIBLY TO 30s subunit of bacterial ribosome, blocking binding of aminoacyl-tRNA to receptor site on mRNA was ribosome complex. This prevents additional a.a. to growing peptide

Question 16

Tet absorption occurs where and is impaired by what food/factors?

Answer 16

Upper small intestine

By: Food (exc, Doxy and Mino), Ions (Ca, Mg, Fe, Al), Dairy prod. and antacids, alkaline pH

Question 17

Photo toxicity of which Tetracycline

Answer 17

Demecycline: Tetracycline with C7 chlorine, absorb light in the visible region leading to free radical generation and potentially cause severe erythema to sensitive patient on exposure to sunlight.

Question 18

Doxy and Mino

Answer 18

Doxy: Less SEs. Renally safe. More photosensitive
Mino: High SEs. Has reactive a.a. causes serum sickness (discoloration of nails, bones, teeth) More eff. for acne due to lip. sol. OD= 90-100% bioav.
BOTH in doses >100mg ➡️Vestibular toxicity (vertigo, ataxia, n) dizzy HE

Question 19

Expired tetracycline causes what syndrome?

And GI adverse effects?

Answer 19

Funconi like syndrome (renal tubular necrosis, diabetes like symptoms) and extreme cases has been fatal.
GI: Tet modify intestinal flora➡️ suppression of coliform bacteria an overgrowth of pseudomonas, proteus, Staph, Clostridia and Candida

Question 20

DOC for diarr prophylaxis. W/wo food?

Answer 20

Doxy.

WITH or AFTER food, BUT EMPTY STOMACH BETTER ABSORPTION

Question 21

Optical isomerism of Tet.

Answer 21

Epimerization➡️ Epitetracycline

Question 22

Mycoplasma pneumonia is treated by?

Answer 22

Macrolides and Tetracyclines

Question 23

Most common complication of clindamycin is?

Symptoms include? Tx by?

Answer 23

P.colitis (diarrhea): fever, abdominal pain, and bloody
stools.
Oral vancomycin or metronidazole, OTC antidiarrheals not effective

Question 24

Clindamycin active against?

Usual dose?

Answer 24

Gram +ve, -ve and anaerobic bacteria.
150-300mg q8h adults
10-20mg/kg/day q8h children

Question 25

Clindamycin can cause what blood complications?

Answer 25

Blood dyscariasis (esonophilia, thrombocytopenia,
leukopenia)

Question 26

Clindamycin suspension stored at?
should be taken?
available dosage forms?

Answer 26

Room temperature
With or without food
IV, oral and suspension

Question 27

Derivation of Clindamycin

Answer 27

Chlorine-substituted derivative of Lincomycin, derived from Streptomyces lincolnensis

Question 28

-50S -Bacteriostatic -Bioav: PO»IV

Answer 28

Chloramphenicol
usual dose: 50-100mg/kg/day
oral: Chloramphenicol palmitate *PO
IV: Chloram succinate *suk-suk

Question 29

Chloramphenicol metabolism and ADE

Answer 29

Metabolized in the liver by GLUCURONIDATION

ADE: Gray baby syndrome - newborns don’t have enz to metab. this= gray skin color

Question 30

Chloramphenicol DIs and effects

Answer 30

Prolongs serum conc. of Phenytoin, Tolbutamide, Chlorpropramide, Warfarin
Like other bacteriostatic drugs, this antagonizes bactericidal drugs such as Pen/Aminoglycosides

Question 31

AGs bind to 30S ribo in 3 ways

Answer 31

1) Interference w initiation complex
2) Misreading mRNA
3) Breakup of polysomes

Question 32

AG ADEs

Answer 32

Nephrotoxicity- inc. serum creatinine and BUN (blood urea Nitrogen) levels
Neo, Tobra and Genta- most Nephx
Ototoxicity- auditory damage Neo, Kana, Amika
Vestibulotoxic- Strep, Genta

Question 33

Mechanism. Binds to bacterial ribosome’s to inhibit protein synthesis.
Therapeutic use. Methicillin resistant S. aureus (MRSA) infections

Answer 33

Oxazolidinones: Linezolid (po, parenteral)
SE Reversible thrombocytopenia.
DI It can cause serotonin syndrome with antidepressants.